Percolation? Heat soak? Don't drive during summer??

Does it have a 160 thermostat? I wouldn't be worried about that at all. But the OP's car seems to have an issue somewhere in the coolant system.

No, its 180 or 190 with me leaning more towards the 190 thermostst. It was one of the first things I replaced with the wp. I have a brand new 180 sitting in the bag though that I may install.